1. Field of the Invention
The present invention relates to robots and more particularly, to a spherical linkage type surgical robotic arm.
2. Description of the Related Art
With the advances in medical technology, new surgical techniques have been continuously introduced. Fast and low risk surgical techniques that enable patients to recover faster have been the goal of the medical profession, and the very popular minimally invasive surgery in recent years is one of them. For example, endoscopic imaging technology and micro-surgical instruments are used in laparoscopic surgery, so that the surgery can be performed without making a large wound on the body of the patient, not only reducing blood loss in the patient but also enabling the body of the patient to recover quickly from the wound.
However, when performing a laparoscopic surgery, the surgeon needs to insert an endoscopic imaging module and a surgical instrument module into the body of the patient and then to perform the surgery while simultaneously viewing the endoscopic image. Thus, the surgeon will need the assist of a mechanical arm to hold or operate the related surgical instruments so that the surgeon can proceed with the operation.
Conventional robotic arms commonly have a complicated structure and require complicated calculations and precise control to achieve precise allocation. US 2007/0173976 A1 discloses a center robotic arm with five-bar spherical linkage for endoscopic camera. According to this design, each link has a different length (see FIG. 7A and FIG. 7B), therefore, it requires a large amount of calculations to precisely move the outward axis to the desired location.
Further, US2012/0184968 discloses a robotic arm with five-bar spherical linkage, which uses a parallel spherical five-bar linkage. According to this design, the surgical instrument is affixed to an extension portion of one link (see FIG. 15). This designs allows the surgical instrument to pass through the center of spherical rotation, however the other part beyond the center of spherical rotation will be turned with the respective link around the center of spherical rotation. During movement of the link, the large turning angle of the surgical instrument will reduce the readability for the surgeon to read the data being displayed on the surface of the surgical instrument.